<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="" method="post">
    用户名: <input type="text">
    <br>
    密码: <input type="password" name="" id="">
    <br>
    验证码:<input type="text" name="" id="">
    <img src="./4.code.php" alt="">
    <a href="">看不清换一张</a>
    <br>
    <input type="submit" value="登陆">
</form>
</body>
</html>